/*********************************************************************
 * Copyright (C) 2005 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff;

/**
 * A growable array of bytes
 */
public class ByteArray {
    /**
     * The array grow size
     */
    private int growSize;

    /**
     * The current array
     */
    private byte[] bytes;

    /**
     * The current position
     */
    private int pos;

    // The default grow size
    private final static int defaultGrowSize = 1024;

    /**
     * Constructor
     */
    public ByteArray() {
        this(defaultGrowSize);
    }

    /**
     * Constructor
     *
     * @param gs
     */
    public ByteArray(int gs) {
        growSize = gs;
        bytes = new byte[defaultGrowSize];
        pos = 0;
    }

    /**
     * Adds a byte onto the array
     *
     * @param b the byte
     */
    public void add(byte b) {
        checkSize(1);
        bytes[pos] = b;
        pos++;
    }

    /**
     * Adds an array of bytes onto the array
     *
     * @param b the array of bytes
     */
    public void add(byte[] b) {
        checkSize(b.length);
        System.arraycopy(b, 0, bytes, pos, b.length);
        pos += b.length;
    }

    /**
     * Gets the complete array
     *
     * @return the array
     */
    public byte[] getBytes() {
        byte[] returnArray = new byte[pos];
        System.arraycopy(bytes, 0, returnArray, 0, pos);
        return returnArray;
    }

    /**
     * Checks to see if there is sufficient space left on the array.  If not,
     * then it grows the array
     *
     * @param sz the amount of bytes to add
     */
    private void checkSize(int sz) {
        while (pos + sz >= bytes.length) {
            //  Grow the array
            byte[] newArray = new byte[bytes.length + growSize];
            System.arraycopy(bytes, 0, newArray, 0, pos);
            bytes = newArray;
        }
    }
}
